O-Glycosyl hydrolases (EC 3.2.1.-) are a widespread group of naturally-occurring enzymes that hydrolyze the glycosidic bond between two or more carbohydrates or between a carbohydrate and a non-carbohydrate moiety. The International Union of Biochemistry and Molecular Biology (IUBMB) enzyme nomenclature of glycosyl hydrolases (or glycosylases) is based principally on their substrate specificity and occasionally on their molecular mechanism (Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB), Accessed Oct. 24, 2011).
IUBMB Enzyme Nomenclature EC 3.2.1.4 has been designated for a subgroup group of glycosylase-type enzymes termed “cellulases.” Other names used for enzymes belonging to this group include: endoglucanase, endo-1,4-beta-glucanase, carboxymethyl cellulase, and beta-1,4-glucanase. The reaction catalyzed by enzymes belonging to this group is the endo-hydrolysis of 1,4-beta-D-glycosidic linkages in cellulose, lichenin, and cereal beta-D-glucans (such as barley beta-glucan). Since the predominant activities of the disclosed cellulase of the present invention are the endo-hydrolysis of barley beta-glucan and carboxymethyl cellulose, it is appropriately ascribed the IUBMB Enzyme Nomenclature EC 3.2.1.4.
An alternative classification of glycosyl hydrolases is based on amino acid sequence similarities (Henrissat, B. Accessed at UniProt Oct. 26, 2011). According to this classification scheme, glycosyl hydrolases can be divided into more than 70 families. Based on a comparison of the primary amino acid sequence of the disclosed cellulase of the present invention with the sequences of other glycosyl hydrolases contained in public databases, the disclosed cellulase of the present invention may be assigned to glycosyl hydrolase Family 5. This family contains more than 20 endoglucanases (IUBMB Enzyme Nomenclature EC 3.2.1.4) whose predominant catalytic activity is the endo-hydrolysis of beta-1,4-glycosidic linkages in cellulosic substrates. Using this second way of classifying enzymes provides further support for the conclusion that the disclosed cellulase of the present invention should be ascribed the IUBMB Enzyme Nomenclature EC 3.2.1.4.
Cellulases are used for a variety of industrial and commercial purposes including but not limited to oil and gas exploration, food and beverage, alcohol production potable or fuel, e.g. brewing, ethanol, wine, flavor, fragrance, textile, detergents, paper, pulp, environmental, and agriculture, as well as in research purposes. (Rebecca S. Bryant, Erie C. Donaldson, Teh Fu Yen, George V. Chilingarian, Chapter 14 Microbial Enhanced Oil Recovery, In: Erle C. Donaldson, George V. Chilingarian and Teh Fu Yen, Editor(s), Developments in Petroleum Science, Elsevier, 1989, Volume 17(B):423-450) (M. Karmakar and R. R. Ray, 2011. Current Trends in Research and Application of Microbial Cellulases. Research Journal of Microbiology, 6:41-53.).
A typical corollary activity and expense to oil and gas discovery and drilling operations is the treatment of fluids used and or produced by such operations. For example, the drilling of wells, the washing and prepping of wells (“well completion”), hydraulic fracturing operations, and oil and gas processing, all typically produce thousands of gallons of a contaminated by-product fluid. Often the by-product fluids created by such operations are called “flowback fluids,” as the liquids typically flow back out of the wellbore to the surface. The by-product fluid, or flowback, must typically be treated for either disposal or reuse.
Need for more efficient means to treat flowback fluids
As the treatment of flowback fluids in the gas discovery and drilling industry requires considerable resources and time, a need exists for efficient methods or compositions to treat flowback fluid. Additionally, as gas discovery and drilling operations typically require fresh (e.g. cleaned or filtered) fluids, a significant need exists for methods to treat flowback fluids to allow the re-use of such fluids for additional gas discovery and drilling operations.